Action Wall Ties’ expertise was sought to undertake the securing of large concrete copings to the Hanger Lane underpass retaining walls. The specification, provided by Transport for London, was to introduce a pattern of large stainless steel fixings to be drilled down into the concrete of the wall.
This presented a series of obstacles to overcome. Firstly, to enable the proposed drilling we had to initially design equipment and methods to enable the efficient drilling for the pattern of fixings. Secondly, we had to be self-sufficient for the delivery of water and electricity supply to the working place on truck mounted working platforms, together with all that is involved in working on the closure of a major road at night.
To enable the efficient drilling Action Wall Ties designed and manufactured four working saddles that clamped over the head of the wall, each supporting two diamond core drilling rigs set at the correct spacings with connections for water, electricity and lighting.
To provide water to the diamond drills we mounted a large water tank and pumps with a diesel generator supplying power into a large Sprinter van, together with other mobile generators which provided the services required for the proposed works. (Pic hang 1)
With the access platforms in place the AWT designed manufactured drilling saddles were lifted and clamped into place and connected to the services (as listed above). Adopting wet diamond drilling techniques a pattern of 20mm holes 400mm deep were drilled. Each saddle was set in place to drill two holes simultaneously, and a second set by sliding the rig forward before resetting the saddle, deploying four maned drilling saddles to meet with the program.
The pre-drilled holes were cleaned before we resin bonded 16mm stainless steel grip bars, and made good the disturbed areas with coloured concrete repair mortar.